Many molding machines are known in the prior art which will blow mold a parison into a finished container. Prior art molding machines commonly use a preform which has been heated prior to delivery of the parison to the molding machine. Such arrangements are common in the prior art because the manufacture of the preform and the blowing of the preform into a finished container are generally conducted in the same machine, as in well known injection-blow molding machines and extrusion-blow molding machines. Further generally in the prior art, where blow molding machines are known to accept relatively cool preforms or preforms at ambient temperatures, such blow molding machines generally have ovens through which the preforms are carried for heating prior to blowing.
Other prior art blow molding machines which will accept an ambient temperature preform commonly use preforms which are substantially thick discs or shallow plate-like preforms. Such blow molding machines are used where it is desirable to provide bi-axial orientation of the finished container in the blow molding machine. Such blow molding machines heat the disc or shallow preform in an oven, then generally stretch the preform in one direction to produce molecular orientation in the direction of stretching and thereafter blow the stretched preform in directions substantially perpendicular to the direction of stretching to form a finished container with bi-axial orientation therein.